Chronic pain is a health problem that has been surging recently. Studies conducted thus far show that performing stimulation or injection therapy with a needle on a pain origin region or point is one of the effective way to treat or manage chronic pain.
An example of a therapeutic needle for musculoskeletal pain is disclosed in U.S. Pat. No. 2,409,979, which will be explained in view of FIGS. 9 and 10.
As shown in FIGS. 9 and 10, a needle includes a body 10, which is circular in cross-section and which has a tubular bore 11, terminating in a discharge end or outlet defined by the edges of the wall of the body 10. The body 10 is bent to provide a curved surface 15 of diminishing area, extending in the direction of the outer parts of the end portion of the needle. This curved surface 15 is interrupted by the edges, which, at their points of merger with the curved surface 15, provide cutting edges 17. To provide the sharp cutting edges 17, beveled surfaces 18 extend at proper angles with respect to the curved surface 15. Accordingly, a slitting function is achieved as the needle is caused to pierce the tissue. A tissue-piercing point 16 is defined at the point of juncture of the surfaces 18 and 15.
However, while such a medical needle of prior art having sharp cutting edges and tissue-piercing point enters a patient's body to an object region or point, it can cause serious consequences such as severe bleeding due to penetration of blood vessel, serious neuropathy due to damage of nerves.
Particularly, when performing epidural anesthesia by using the medical needle of prior art, the needle should be inserted into an epidural space of a dura mater, which surrounds brain and spinal cord. During this procedure, there was a high risk of dural and arachnoidal laceration and corresponding CSF leakage with the sharp tissue-piercing point of the needle, which may lead to severe complication like a dural puncture headache. Also, when inserting the medical needle of prior art into the dura mater to extract cerebrospinal fluid, the sharp cutting edges and tissue-piercing point of the needle may damage the spinal cord and nerve roots surrounded by the dura mater, thereby causing serious problems such as physical paralysis and neuropathy.
Further, the medical needle of the prior art leaves many lacerations at the tissues since the sharp cutting edges split the tissues as it enters the patient's body.